Thermionic translating device



A. McL. NICOLSON.

THERMIONIC TRANSLATING DEVICE.

APPLICATION FILED FEB. 19. I916- Patented Jan. 25, 1921.

'' lJ NlTED STATES PATENT orrlca.

ALEXANDER MbLEAN NIGOL SON, OF NEW YORK, Ill.

Y., assrenon 'ro 'wns'rmur ELECTRIC COMPANY, INCORPORATED, OF NEW YORK, N. Y., A, GQRPQBATI N OF NEW YORK;

TEERMIONIC TRAN BL ATIN G DEVICE.

specification of Letters Patent. Patented Jan. 25, 1921.

Application filed February 19, 1916. Serial No. 79,428.

York, have invented certain new and useful Improvements in Thermionic Translating Devices, of which the following is a full,

clear, concise, and exact description.

This invention relates to thermionic translating devices and more particularly to vacuum tube devices in which the discharge of electrons from a heated cathode to an anode is made to vary in accordance with variations in an electromotive force impressed between the cathode and a third electrode.

Its object is to produce a large output from such a device.

.A well-known type of thermionic translating device is the so-called audion having three electrode elements, namely, a cathode composed of a heated filament, an anode or plate and an input electrode or grid. When such a device is used, for example, as a telephone repeater, the attenuated voice currents to be amplified and re transmitted are caused to vary the potential between the filament and grid, thereby superposing high frequency variations onthe space current flowing between the plate and filament by' virtue of the thermionic emissions from the filament and an external constant electromotive force normally impressed between the said filament and theplate. This superposed high frequency' current, {01 output current, has the same frequency characteristics as the input curren In the present invention the grid element is omitted, and there are employed two thermionically active or electron emitting electrodes which are located on opposite.

sides of a dielectric separator, such as a sheet of mica, in an arrangement analogous to that of a condenser. An anode is placed opposite and exposed to the thermionic dis-- charge from each of these electrodes. The varying input electromotive forces are im-' pressed between these two electrodes and serve to var the passage of electrons from the said e ectrodes to their respective anodes. The electrodes, in effect, function mentary perspective view of the device of' my invention, and. Fig. 2 illustrates.dia-

grammatically how such a device may be employed in a circuit to amplify telephonic currents.

In Fig. 1, 3 is a highly evacuated vessel withinwhich aremounted in any suitable manner the anode or plate members 4 and 5, and the two cathodes 6 and 7, which in thls case are shown as filamentary in form. Between the cathodes 6 and 7 is a dielectric plate 8 of mica or other suitable material and of sufficient size.to prevent any shortcircuitlng action, due'to the passage of electrons from one cathode to the other.

In a typlcal application of this invention, such as that illustrated in Fig. 2, the filaments 6 and 7 are heated to incandescence by the batteries 9 and 10,- respectively, and thus become thermionically active and discharge electrons to their respective anodes 4 and 5. For reasons given below, batteries 9 and 10 should preferably be so poled with' which receives the attenuated -currents to be amplified. Cathode 6 is also connected through primary winding 14 of the output transformer 19 and through battery 15 to anode 4. Similarly cathode 7 is connected through primar winding 16 and battery 17 to anode 5. atteries 15 and 17 are of course so poled as to make anodes 4 and 5 away with the necessity of a positive with respect to their corresponding cathodes 6 and 7 and are preferably of the same magnitude.

When the equilibrium of the system is undisturbed by any flow of current in the winding 13, it is evident that the two cathodes 6 and 7 will be at the same potential with respect to each other and with respect to their respective anodes 4 and 5.

The space currents flowing from the anodes 4 and 5 to the cathodes 6 and 7 will therefore afiect the windings 14 and 16 difi'erentially. Furthermore, each point on one filament will lie adjacent a point of the same polarity on the other filament; the potential drop due to the heating current in one filament being compensated for by an equal potential drop in the other. This results in a uniform action between the two filaments throughout their len ths and does battery such as is employed in the grid circuit of the ordinary audion to maintain artificially the proper potential difference between the input and cathode elements. Considering now the operation-of the device, it is known that a positively charged body located near an electron emitting cathode serves to increase the space current between the cathode and.

an anode maintained positive thereto, and conversely that a negatively charged body will decrease the space current. Bearing in mind the condenser analogyabove pointed out, it will be seen that in the present arrangement the thermionic current from the more negative cathode will be increased by the presence of a positive charge on the cathode located on the opposite side of the dielectric 8, and conversely the current from the less negative cathode will be decreased by the ne ative charge on the opposite side of the di ectric, these current changes being additive to produce in winding 19 an amplified current having the same frequency characteristics as the currents initially impressed on winding 13,

What is'claimed is: a

1. A thermionic translating device having two cathodes, each serving as a control electrode for the other..

2. A translating device having two thermionically active electrodes in close proxim-' ity to one another and separated by a dielectric.

3. A translating device having a dielectric plate, a thermionically active electrode on each side of said plate and an anode opposite one of which is connected to one side of said line, the other heated electrode being connected to the other side of'said line, and electron receiving means associated with said heated electrodes, one of said heated electrodes serving as a control electrode for the electron flow from the other of said heated electrodes.

6. A translating device having a dielectric separator, two thermionically active filaments of similar size and form located symmetrically on opposite sides ofsaid separator, and a heating .battery individualto each of said filaments, like poles of said batteries being connected to adjacent terminals of said filaments.

7. A translating device having a dielectric. plate, a thermionically active electrode on each side of said plate, an anode opposite each of said electrodes, means for impressing a constant electromotive force between said electrodes and said anodes, and means for varying the electrostatic field between said electrodes. I 1

8. An energy translating device comprisin a highly evacuated vessel, two thermionically active electrodes and two anodes within said vessel, an input transformer having one terminal of its secondary winding connected to'each of said electrodes and an output transformer havingtwo, primary windings said primary windings being connected each toone of said anodes.

9. An energy translating device comprising an evacuated vessel, two thermionically active electrodes and two anodes within said vessel, an input transformer having one terminal of the secondary winding connected to each of said electrodes, an output transformer having two primary windings and a secondary winding, and two output circuits each including one of said anodes and one of said primary windings, said output circuits being connected difi'erentially with respect to. said secondary winding.

10. In a translating device, means for creating two electron streams, an electrode in each of said streams for controlling the electron flow in the other of said streams.

11. In a translating device, means for creating two electron streams, an electron emitting cathode in each of said streams for controlling the electron flow in the other of said streams.

12. A translating device comprising an evacuated vessel, two electron emitting electrodes within said vessel, a dielectric within ing more than two electrodes, two of said electrodes being heated cathodes each serving as a control electrode for the other, and each of said cathodes being at a lower potential than another of said other electrodes in said device.

15. An evacuated vessel containing two cathodes and two anodes and means whereby one of said cathodes serves as a control electrode for the other of said cathodes.

16. An evacuated vessel containing two electrodes, two other electrodes between said firsttwo electrodes, and a dielectric sheet between said last two electrodes.

17. An evacuated vessel containing two anodes, two cathodes between said two anodes, and a dielectric sheet between said cathodes.

18. An evacuated vessel containing electrodes, connections therefor providing a plurality of sets of electron paths, and a dielectric body separating one of said sets from another.

19. A thermionic device comprising an anode and a thermionic cathode, a source of voltage connected between said anode and cathode, means for controlling the space current between said anode and cathode, said means comprising a second cathode, and a shieldof dielectric material between two of said electrodes.

20. An evacuated vessel containing an anode and a thermionic cathode, a source of voltage connected between said anode and cathode, means for controlling the space current between said anode and cathode, said means comprising a second cathode, and means comprising a dielectric substance intercepting a flow of electrons from one of said cathodes to said anode.

21. In a translating device comprising a thermionic cathode and an anode, means for creating an electron stream between said anode and cathode, means comprising a heated electrode for controlling said electron stream, and a dielectric body between said heated electrode and said anode.

22; An evacuated vessel containing a plurality of sets of cathode and anode surfaces, and a dielectric body separating one of said sets from another.

23. The combination of a line, a thermionic device comprising two heated electrodes one of which is connected to one side of said cathode, a control electrode, said cathode and control electrode being of the same form and having corresponding active portions thereof in parallel space relation.

25. An evacuated vessel containing two cathodes and two anodes, means for supplying space current between said cathodes and anodes, the drop of potential between one anode and its respective cathode being approximately the same in value as the drop of potential between the other cathode and anode, and means whereby one of said cathodes serves as a control electrode for the other of said cathodes.

26. A thermionic device comprising an anode, a cathode and a control electrode,two of said electrodes being filamentary in form, means for supplying current through said filamentary electrodes, said filamentary electrodes being of the same shape and arranged in parallel space relation whereby each point on one is opposite a point of the same polarity and potential on the other.

27. A thermionic amplifier comprising a plurality of sets of electron paths, each set comprising cathode, anode and control electrodes, one of said electrodes for one of said sets being positioned and connected to serve as a different one of saidelectrodes for another of said sets.

In witness whereof, I hereunto subscribe my name this 17th day of February A. D., 1916.

ALEXANDER McLEAN NICOLSON. 

